Problem with laptop

We just got our old laptop back from a friend who works on computers on the side.

we noticed that the right side of the keyboard, letters j,k,l,o,p,i, & U instead of typing those letters when you click that key, it types the number that is in the upper right corner of that key. if you push the fn key it will type the letter that is what is suppose to be typed, but you have to use the fn key every time if you want to use those letters . i called the guy that worked on this laptop and he thinks it's in the f2 button when you first turn on the computer. but we can't find it in there.

anybody know how to fix this, I really don't want to send it back to him to fix. he does alot for us and works on our computers for free. I'd just rather fix this one and be done with it. i figure it's a simple fix, but not sure what to do.

Let me know what info on the computer you need in order to help me with this

I have windows XP and the laptop is a gateway about 8 to 9 years old.